E.3 Radioactive decay SL Flashcards
Isotopes
Variants of the same element with the same number of protons but different numbers of neutrons. They can be stable or unstable, leading to radioactive decay.
Alpha Decay
A type of radioactive decay where an unstable nucleus emits an alpha particle (2 protons and 2 neutrons), transforming into a different element with a mass number reduced by 4 and an atomic number reduced by 2.
Beta-minus Decay
A decay process where a neutron in the nucleus transforms into a proton and emits a beta-minus particle (electron) and an antineutrino, leading to an increase in the atomic number by 1.
Beta-plus Decay
In this decay, a proton is converted into a neutron, emitting a positron (beta-plus particle) and a neutrino. The atomic number decreases by 1, changing the element.
Gamma Decay
Emission of gamma rays (high-energy photons) from an excited nucleus, leading to a decrease in energy but no change in the atomic or mass numbers.
Background Radiation
Low-level radiation present in the environment, originating from naturally occurring sources, cosmic rays, and human-made sources. It affects the count rate in radiation measurements.
Penetrating Ability
The capacity of nuclear radiation (alpha, beta, gamma) to pass through materials. Alpha particles are stopped by paper, beta by aluminum, and gamma rays require thick lead or concrete.
Ionising Ability
The ability of nuclear radiation to strip electrons from atoms, creating ions. Alpha particles have the highest ionising ability, followed by beta particles, with gamma rays being the least ionising.
A device used to detect and measure nuclear radiation by counting the number of radiation particles detected per unit time.
Geiger-Müller Tube
Radiation Safety Precautions
Strategies to minimize exposure to ionising radiation, including minimizing time spent near sources, maximizing distance from sources, and using appropriate shielding materials.
What is Half-life (T_1/2)
The time required for half the nuclei in a sample of a radioactive isotope to decay. It is a measure of the stability of the isotope, with longer half-lives indicating greater stability.
Becquerel (Bq)
The SI unit of radioactivity, defined as one decay per second. It measures the rate at which a sample of radioactive material decays.
Exponential Decay
A process by which the quantity of a radioactive substance decreases over time at a rate proportional to its current value, characteristic of radioactive decay.
Carbon Dating
A method for determining the age of an object containing organic material by using the properties of radiocarbon (14_C), a radioactive isotope of carbon.
Activity
The rate at which a sample of radioactive material decays, measured in becquerels (Bq). It decreases over time as the sample decays, following an exponential decay pattern.
Mass Defect
The difference in mass between a nucleus and its constituent nucleons when separated. It’s the mass equivalent of the binding energy that holds the nucleus together.
Binding Energy
The energy required to disassemble a nucleus into its separate protons and neutrons, indicative of the nucleus’s stability.
Binding Energy per Nucleon
A measure of the stability of a nucleus, calculated as the total binding energy divided by the number of nucleons. Peaks with iron, indicating maximum stability.
Mass-Energy Equivalence (E=mc²)
Einstein’s theory that mass and energy are equivalent and interchangeable, foundational for understanding nuclear reactions and the energy released in them.
Strong Nuclear Force
The force that overcomes electrostatic repulsion between protons to hold the nucleus together, acting only at very short ranges within the nucleus.
